1. Field of the Invention
The present invention relates generally to surgical instruments, and specifically, to tool bits, such as, drilling bits, tapping bits, cutting tips of osteotomes, and the like, for use particularly in the field of oral surgery, and more particularly in the field of dental implantology.
2. Background of the Related Art
Dental implants are surgically implanted in a patient""s jawbone to provide anchors for prosthetic devices such as artificial teeth, crowns, bridges, dentures and the like. Dental implants allow people who lose their teeth to be able to comfortably smile, speak, and chew.
Typically, the dental implant that is implanted in the bone of a patient""s jaw supports a socket. This socket is accessible through the overlying gum tissue for receiving and supporting one or more dental attachments or components. In turn, these components are useful to support the prosthodontic restoration.
The first step for installing an implant usually involves making an incision in the patient""s gum or gingiva. Next, typically, a hole or osteotomy is formed in the jawbone of the patient. This may involve widening of a pre-existing cavity or the formation of a fresh one. The implant is then fixtured into the osteotomy. More than one osteotomy may be prepared to support a plurality of implants. Once the implant is properly secured in its subgingival position in the osteotomy a healing screw is threaded tightly over the implant.
This is followed by a healing period in which the bone is allowed to grow and surround and retain the implant. This process is called xe2x80x9cosseointegration.xe2x80x9d The gum tissue is also allowed to heal over the implant and the healing screw. For implants in the mandible (lower jaw), healing typically requires about three months; for implants in the maxilla (upper jaw), the healing period is usually about six months.
After the osseointegration occurs and the gum has healed, the gum is reopened by making an incision in it and the healing screw is removed. A suitable healing abutment is attached to the implant. A second healing period ensues in which the gum tissue is allowed to heal around the healing abutment. Typically, this second healing period lasts from four to eight weeks.
After the second healing period, the healing abutment is removed from the implant. Typically, an impression is taken of the patient""s mouth to fabricate a prosthesis or dental restoration. An abutment which supports the final restoration is attached to the implant. Lastly, the restoration is cemented or screwed to the abutment and/or implant to complete the placement of the prosthodontic restoration in the patient""s mouth.
The step of forming an osteotomy typically involves drilling a hole in the patient""s jawbone, utilizing one or more suitable drilling bits. This can be a difficult procedure and can cause discomfort and trauma for the patient, at least partially, due to the pain and shock involved with the penetration of a relatively large drilling bit in a person""s jawbone. Drilling in high bone densities can further exacerbate and complicate the osteotomy preparation.
The high rotational drilling speeds typically involved can also generate a significant amount of heat. This is especially true since the osteotomy is not a through hole. Disadvantageously, the large amounts of heat can cause bone xe2x80x9cnecrosisxe2x80x9d due to burning. Again, this adds to the trauma and suffering of the patient, and can inhibit the desired healing of the bone and osseointegration of the implant.
The high rotational drilling speeds can also result in high frictional forces and torques between the bone and the drilling bit. Undesirably, this increases the risk of bone fracture, and again this is detrimental to the patient. Moreover, the high frictional forces and torques may cause breakage of the drilling bit. Disadvantageously, this further complicates the procedure and adds to the trauma of the patient.
In some cases, dental counterbores are utilized to countersink the osteotomy for receiving a particularly configured implant. Also, dental threadformers may be used to thread the osteotomy for receiving a threaded implant. Both counterbores and threadformers involve removal of bone material and can cause some or all of the above-mentioned disadvantages.
In some instances, an osteotome is used to form an osteotomy in soft bone. An osteotome typically has a cutting tip that is manually manipulated by the dental practitioner to cut/compress the soft bony material. Again, the use of conventional osteotomes can suffer from some or all of the above-mentioned disadvantages.
As indicated above, it can be difficult to perform osteotomy preparing procedures efficiently, and without causing significant discomfort and trauma to the patient. Moreover, the drilling bits, counterbores, threadformers, and osteotome cutting tips are exposed to frictional forces and corrosive environments (in the patient""s mouth and possibly during sterilization). As a result, in many cases, these instruments have to be replaced frequently since wear and corrosion reduce their effectiveness. Disadvantageously, this also adds to the cost of the implant procedure.
Accordingly, it is an object and advantage of the present invention to overcome some or all of these limitations by providing an amorphous hard carbon coated tool bit for a dental drilling/cutting system. In one preferred embodiment, the coating comprises diamond-like carbon (DLC). In another preferred embodiment, the coating comprises amorphous diamond. In other embodiments the coating can comprise crystalline diamond or a combination of two or more of diamond-like carbon (DLC), amorphous diamond and crystalline diamond. The tool bit preferably includes drilling bits, threadformers, counterbores, and cutting tips of osteotomes for preparing an osteotomy in a patient""s jawbone. The tool bit can also include other dental cutting tools, for example, a root canal file.
Though there are a wide variety of commercially available xe2x80x9chard carbonxe2x80x9d coatings, the present invention provides certain novel and unique benefits and advantages over the prior art in the field of oral surgery, and particularly in the field of dental implantology as related to the preparation of an osteotomy in a patient""s jawbone. One advantage of the hard carbon coating is that it provides a reduced coefficient of friction (enhanced lubriciousness) between the tool bit and the jawbone, and desirably improves the cutting performance. Some of the other benefits and advantages arise as a consequence of the coating properties of high mechanical hardness (wear resistance), corrosion resistance, and high thermal conductivity. Some or all of these desirable properties of the hard carbon coating translate into reduced discomfort for the patient, reduced chances of accidents, bone fracture and bone necrosis, increased operational ease for the dental surgeon, saving of valuable time, and reduction in the cost of the implant procedure.
In accordance with one embodiment of the present invention, a tool bit for a dental drilling/cutting system is provided. The tool bit is adapted for preparing an osteotomy in a jawbone. The tool bit generally comprises a mounting shank and a cutting head. The mounting shank is sized and configured to interface with a handpiece of the dental drilling/cutting system. The cutting head includes a plurality of cutting edges/surfaces for rotatingly cutting bone/tissue material. A coating of hard carbon is applied on the cutting head. This greatly reduces friction and enhances the cutting performance of the tool bit.
In accordance with another embodiment of the present invention, a dental drilling bit is provided for preparing an osteotomy in a jawbone. The drilling bit generally comprises a mounting shank and a cutting head coated with an amorphous hard carbon film. The mounting shank has a chuck that is sized and configured to interface with a handpiece of a dental drilling system. The chuck has a generally I-shaped flat side and a generally semi-circular disk above and adjacent to a generally semi-circular groove. The cutting head includes a plurality of cutting edges for rotatingly removing bone material to form an osteotomy having a diameter in the range from about 1.5 mm to about 6 mm. Advantageously, the amorphous hard carbon film reduces the friction between the cutting head and bone material to enhance the cutting performance of the drilling bit.
In accordance with a further embodiment of the present invention, a dental drilling system for preparing an osteotomy is provided. The dental drilling system generally comprises a tool bit and a handpiece. The tool bit includes a cutting head for removing bone/tissue material to form an osteotomy. The handpiece holds the tool bit and is adapted to provide rotational motion to the tool bit. A coating is provided on the tool bit in the form of diamond-like carbon (DLC) for improving the cutting performance of the tool bit.
In accordance with one embodiment of the present invention, a method of forming an osteotomy using a dental drilling system is provided. The dental drilling system includes a tool bit with a cutting head that is adapted to remove bone material. The method includes the step of positioning the tool bit at a selected osteotomy site. The tool bit has a portion that is coated with amorphous hard carbon. The tool bit also has bands for indicating the depth of the osteotomy. Rotational motion is provided to the tool bit by utilizing a handpiece of the dental drilling system. The tool bit is withdrawn from the osteotomy when one of the bands indicates that the selected osteotomy depth has been reached.
In accordance with another embodiment of the present invention, a method of making a tool bit for a dental drilling system is provided. The tool bit is adapted to create an osteotomy. The method includes the step of providing a mounting shank on the tool bit. The mounting shank has a chuck at one end for interfacing with a rotation-producing handpiece of the dental drilling system. A cutting head with a plurality of cutting edges is then provided on the tool bit. An amorphous hard carbon coating is then formed on the cutting head of the tool bit. This reduces the friction between the cutting head and bone material and enhances the cutting performance of the tool bit.
In accordance with yet another embodiment of the present invention, a dental tool is provided for preparing an osteotomy in soft maxillary bone. The dental tool generally comprises a cutting tip in mechanical communication with a handle. The cutting tip includes a cutting head with a plurality of cutting surfaces for axially and rotatingly cutting/compressing the bone. The handle permits manual manipulation of the cutting tip. A film of hard carbon is applied to at least a portion of the cutting tip. Advantageously, the hard carbon film improves the lubriciousness between the cutting tip and the bone.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such objects and advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.
All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.